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Function documentation Requests Parsing  Locate the document in its SAP Library structure

Use

HTTP Provider Service running on the Java dispatcher parses incoming HTTP requests to determine which server process to direct them to. Then, additional request parsing occurs on the corresponding server process so that the appropriate module is invoked to process it.

Features

There are two scenarios that have implication on how HTTP Provider Service parses requests. These are:

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       1.      HTTP Provider Service is running, Web Container Service is stopped.

       2.      Both HTTP and Web Container services are running.

Running HTTP Provider Service Only Scenario

When running HTTP Provider Service while Web Container Service is stopped, you can run web sites that contain static web resources only. No servlets or JSPs can be served by the J2EE Engine in this case.

For this scenario, a request URL may contain an HTTP alias, or simply the directory path to the requested resource (relative to the server’s root directory). In either case, HTTP Provider Service running on the dispatcher parses the request and directs it to a randomly selected server in the cluster that has the HTTP Provider Service started on it (determined using the J2EE Engine Load Balancing System). The HTTP Provider Service running on server processes then parses the request to determine the location of the requested resource, the HTTP method to be performed, and so on.

This graphic is explained in the accompanying text 

When you run HTTP Provider Service without Web Container Service, you cannot execute PUT requests to web resources on the J2EE Engine.

Running Both HTTP Provider and Web Container Services Scenario

In this case, you can deploy and run J2EE web applications on the J2EE Engine. The request URL for a web application contains its application alias. HTTP Provider Service running on the Java dispatcher parses the request and based on the load balancing mechanism determines which server node to direct the request to.

The server-side request parsing, in this case, is performed first by the HTTP Provider Service, and then (only if the request is directed to a deployed web application) by the Web Container Service. Based on its configuration, the latter determines which module to process the request. For example, each request to a file with jsp extension is processed by the JSPServlet class. Also, each PUT request is processed by the PutServlet class.

See also:

Load Balancing by the Java Dispatcher (in Architecture Manual)

Load Balancing for J2EE Web Applications (in Architecture Manual)

 

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